Custom Search

News

Monday 03 February 2003

Roles of human liver cytochrome P450 3A4 and 1A2 enzymes in the oxidation of myristicin.

By: Yun CH, Lee HS, Lee HY, Yim SK, Kim KH, Kim E, Yea SS, Guengerich FP.

Toxicol Lett 2003 Feb 3;137(3):143-50

The aim of this work was to identify the form(s) of human liver cytochrome P450 (CYP) involved in the hepatic transformation of myristicin to its major metabolite, 5-allyl-1-methoxy-2,3-dihydroxybenzene. When microsomes prepared from different human liver samples were compared, the activity of 5-allyl-1-methoxy-2,3-dihydroxybenzene formation was well correlated (r(2)=0.87) with nifedipine oxidation (a marker of CYP3A4). With a microsomal sample having high CYP3A4 activity, microsomal oxidation of myristicin to the major metabolite (5-allyl-1-methoxy-2,3-dihydroxybenzene) was markedly inhibited by gestodene and ketoconazole, selective inhibitors of CYP3A enzymes, but not by any of several other P450 inhibitors. Antibodies raised against CYPs 3A4 and 1A2 could also inhibit the oxidation of myristicin, but antibodies recognizing other CYPs had no effect. The oxidation of myristicin to 5-allyl-1-methoxy-2,3-dihydroxybenzene was catalyzed by purified bacterial recombinant CYPs 3A4 and 1A2. These results provide evidence that CYP3A4 (and possibly other CYP3A enzymes) and CYP1A2 play roles in the formation of the major metabolite, 5-allyl-1-methoxy-2,3-dihydroxybenzene.

Use of this site is subject to the following terms of use